Adsorption of PEO in highly confining porous glass

Adsorption of poly(ethylene oxide) within porous glass, from aqueous soluti ons, was investigated as a function of the polymer molecular weight, pore d iameter, concentration, and time, using differential refractometry. The kin etics of the process was found to depend on the ratio of pore diameter to t he correlation length in the polymer solutions. The adsorbed amount exhibit ed a dependence on pore diameter for the longer molecular weights, with an unexpected observation of a higher adsorption in smaller pores. This observ ation is explained by the interplay between geometry-dependent enthalpic ga in due to adsorption and entropic loss due to confinement.